In the manufacture of automotive carpets, and other carpets, the back or underside of the carpet is coated with a polyolefin in order to hold the carpet fibres in place and prevent or reduce early abrasive wear and easy removal of tufts of carpet fibres from the carpet. Such a coating is frequently referred to as a pre-coat. In the form of a pre-coat, the polymer wicks into the carpet and forms both mechanical and chemical bonds to the carpet fibres. Thus, the pre-coat functions to retain the fibres in place by such mechanical and chemical bonding to the fibres.
It is understood that the carpet may have additional backing, especially for sound deadening or as backing sheets, all of which may be referred to as "massback".
A variety of polyolefins are used as pre-coat backing and as a component of sound deadening or backing sheets i.e. "massback", for automotive carpets.
Problems in the mechanical and chemical bonding of the fibres by the pre-coat have developed as a result of changes in the composition of the fibres in the carpet. Additives containing copper, especially cuprous iodide, are now incorporated into or on the nylon fibres to increase the useful life and retain the colour of the fibre. However, it has been found that in the presence of at least some polyolefin pre-coat or massback compositions, such additives actually cause a degradation reaction that affects the bonding between the fibres and the polyolefin backing. The degradation reaction results in the fibres becoming brittle and crumbling within a short period of time under conditions of heat and sunlight. Such conditions are typical ambient conditions in an automobile in many areas and at many times of the year.